There are many applications for data input from a hard copy to a computer system that use automated Optical Character Recognition (OCR), followed by manual verification of the OCR results. Human operators perform the verification step, either by reviewing all the fields in the original document, and correcting errors and rejects discovered in the OCR results, or by viewing and correcting only the characters or fields that have a low OCR confidence level. For example, U.S. Pat. No. 5,455,875, to Chevion et al., whose disclosure is incorporated herein by reference, describes a method for organizing data on a computer screen so as to improve productivity of human operators in verifying OCR results. The method is implemented in document processing systems produced by IBM Corporation (Armonk, N.Y.), in which the method is referred to as “SmartKey.” Such OCR-based methods are useful as long as the OCR results are reliable, so that there are relatively few errors that the operator must correct.
Despite advances in the robustness of optical character recognition (OCR), there are still many document processing applications that do not achieve the requisite level of reliability for OCR-based processing. In these applications, it is necessary for human operators to key data into a computer terminal. The operator views either the paper document itself or an image of the document (or of a selected part of the document) and codes the document contents by typing letters and numbers into the terminal. This sort of manual coding is costly, and there is a need for techniques that can be used to reduce the amount of time that the operator spends keying in each document entry.